holiday for the sailors on board the five american destroyers, now floating in the mediterranean, or barack obama, one man deciding whether or not to use the ships in syria, nothing but somber faces around the tables in the west wing this morning as the president met with the staff. And this afternoon, as secretary of state john kerry stepped before cameras with the intelligence that the syrian army used poison gas and killed over 400 children. Aside from punishing assad, he said an american strike is needed to send a message to our enemies in iran and north korea. We choose to live in a world where a thug and a murderer like bashar al-assad can gas thousands of his own people with impunity, even after the united states and our allies said no. And then the world does nothing about&#231;&#243; it. There will -- will be no end to the test of our resolve and the danger that flows from others who believe they can do as they will. A few hours later, president obama was not nearly as passionate as kerry, saying he has yet to make up his mind on an attack, while most of our allies and even britain wishes he wouldn't. And I assure you, nobody ends up being more war-worry than me. But what I also believe is that part of our obligation as a leader in the world is making sure that when you have a regime that a is -- is willing to use weapons prohibited by national norms on their own people, including women and children, that they are certainly held to account. And just how much more weapons are stockpiled in syria, for a deeper look on what that means here is abc's brian ross. Reporter: Experts say there are hundreds of thousands of weapons in syria, capable to kill many people. It is known they have many weapons. Reporter: And friday, they produced a weapons report on a chemical weapons attack that killed hundreds in the suburb of guda earlier this month. We can't accept a world where the innocent civilians, and men, women, and children are gassed. This threatens our national security interest. Reporter: The expected strike against syria presents a minefield of problems, in the target selection, according to former white house official, richard clark, now an abc consultant, clark says there are two target packages being considered. One, which is related to the chemical weapons use and makes them pay a price. Another one, which makes them pay a much more significant price so that the united states can say this was not a pin prick attack, and we're serious. Reporter: Under the larger attacks, the targets could include syrian air fields, and even perhaps the ministry of defense in downtown damascus. They will have the coordination of that particular building, they can hit that part of the building? They can go right into a ten-foot area, right in a particular office. Reporter: The attacks under either scenario would come largely from destroyers a 100 miles away in the mediterranean, firing cruise missiles. They would like to do it at night, because they could be shot down, they fly low, relatively fast. Reporter: Yet senior officials tell abc news it is unlikely that the chemical weapons themselves at depots across syria will be targeted, if and when there are military attacks. If you are going to hit them, blow them up, are you going to create agent plumes which are going to damage civilian areas? Reporter: He knows all about destroying the chemical weapons, he led the u.N. Team that destroyed iraq's massive stores of them. It is not a simple process, because the consequences are enormous. Reporter: Instead, officials tell abc news that the proposed military strike would target the specific military unit that guards and deploys syria's chemical weapons. They would be a prime target. But even then, there is a dilemma for those who are doing the targeting. Reporter: Until earlier this year, steve simon with the director of affairs, the white house security council, now an abc news consultant and director of the international institute for strategic studies. If you're going to strike in a way that is directly related to chemical weapons use, you would have to hit some part of unit 450. On the other hand, the administration has got to be concerned that chemical weapons stock piles don't leak. Because unit 450 has been so seriously damaged it is not capable of preserving and protecting the integrity of the storage facilities where the cw was located. Reporter: That is because the fear of what would happen if the regime's chemical weapons ended up in the hands of the rebels, where a dominant group in the opposition forces is an al-qaeda affiliate calledal nusra. They can't expect them to exercise restraint. Reporter: The role of the al-qaeda group fighting against assad is one of the great ironies of the united states military strike in syria. 12 years after the attack, united states finds itself on the same side as al-qaeda trying to overthrow the assad regime. It is a great irony. Reporter: They have a variety of military assets. It is not just an ally. It is an organization that has sworn loyalty to al-qaeda and pakistan. The u.S. Will want to weaken it over time, because the strong al-qaeda affiliate in syria will at some point turn against the united states. Reporter: Syria is already bracing for the attack, with some residents fleeing the country into neighboring lebanon. The syrian president assad said his country will fight back. And in iran, the military officials have said they will strike against israel and perhaps the u.S., As well. I wouldn't be surprised if the iranian-backed tourists, including, not limited to hezbollah, launch attacks throughout the middle east on u.S.-Related facilities. Now, that may not be an embassy but it could be a facility that seems to be american, perhaps an american airplane. Reporter: So tonight at the white house, the find preparations are being made for what will be another controversial u.S. Military action. I think the targets have all been ready to go. We'll keep you posted on the latest developments on abc news

This transcript has been automatically generated and may not be 100% accurate.

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